Fossil fuels are currently the predominant source of energy in the world. Due to concerns such as carbon dioxide emissions and the finite nature of the supply of fossil fuel, research and development and commercialization of alternative sources of energy have grown significantly over the preceding decades. One focus of research and development is hydrogen fuel cells, which can quietly and efficiently generate electrical power while producing only heat and water as significant byproducts.
One type of hydrogen fuel cells is a proton exchange membrane (PEM) fuel cell. A PEM is a membrane generally made from an ionomer and designed to conduct protons while being impermeable to gases such as oxygen or hydrogen. PEM fuel cells have potential to replace internal combustion engines, the current dominant source of energy for motor vehicles and other such mobile propulsion applications. At the anode electrode of a PEM fuel cell, hydrogen molecules are oxidized to hydrogen ions, i.e., protons, and electrons. The protons permeate across a polymer membrane that acts as an electrolyte (the PEM) while the electrons flow through an external circuit, ending up at the cathode where they combine with protons and oxygen to form water. Some of the energy of the electrons is captured as they flow through the external circuit, thus generating electric power. At the cathode of a hydrogen/air fuel cell, oxygen reacts with electrons and protons that migrate across the PEM to produce water. Thus, in the past decade, research and development have focused on the membrane composition and structure of the PEM and methods of forming the PEM, where the PEM structure is robust and the manufacturing process thereof is simplified.
Alkaline anion-exchange membrane fuel cells (AAEMFCs) are a potentially significant technology that could compete with the more popular and well-studied PEM fuel cells for a variety of applications. The alkaline anion exchange membrane (AEM or AAEM) is a membrane generally made from ionomers with positively charged fixed ion-exchange sites and designed to conduct anions while being impermeable to gases such as oxygen or hydrogen. During alkaline fuel cell operation, the membrane conducts hydroxide ions. A fundamental drawback of all AEMs is the fact that hydroxide anions have a lower inherent mobility than protons which adversely affects ionic conduction in an AEM. To compensate for these two problems, membrane researchers have focused their attention on the use of high ion-exchange capacity polymers, but this strategy exacerbates the problems of membrane brittleness in the dry state and poor mechanical strength when the membrane is fully hydrated.
Therefore, a heretofore unaddressed need exists in the art to address the aforementioned deficiencies and inadequacies.